• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.22-29
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• 2023

In the evaluation of seismic performance for structural materials and components, the loading rate and axial force can have a significant impact. Due to time-delay effects between input and output displacements, It is difficult to apply high-rate displacement in cyclic tests and hybrid simulations. Additionally, the difficulty of maintaining a consistent vertical load in the presence of lateral displacement has limited fast and real-time tests performed while maintaining a constant vertical load. In this study, slow, fast cyclic tests and real-time hybrid simulations were conducted to investigate the rate dependency and the influence of vertical loads of Isolation Bearing. In the experiment, the FLB System including an Adaptive Time Series (ATS) compensation and a state estimator was constructed for real-time control of displacement and vertical load. It was found that the vertical load from the superstructure and loading rate can have a significant impact on the strength of the seismic isolation bearing and its behavior during an earthquake. When conducting experiments for seismic performance evaluation, they must be implemented to be similar to reality. This study demonstrates the excellent performance of the system built and used for seismic performance evaluation and enables accurate and efficient seismic performance evaluation.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.37-46
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• 2023

Dynamic soil properties are essential factors for predicting the detailed behavior of the ground. However, there are limitations to gathering soil samples and performing additional experiments. In this study, we used an artificial neural network (ANN) to predict dynamic soil properties based on static soil properties. The selected static soil properties were soil cohesion, internal friction angle, porosity, specific gravity, and uniaxial compressive strength, whereas the compressional and shear wave velocities were determined for the dynamic soil properties. The Levenberg-Marquardt and Bayesian regularization methods were used to enhance the reliability of the ANN results, and the reliability associated with each optimization method was compared. The accuracy of the ANN model was represented by the coefficient of determination, which was greater than 0.9 in the training and testing phases, indicating that the proposed ANN model exhibits high reliability. Further, the reliability of the output values was verified with new input data, and the results showed high accuracy.

• Journal of Industrial Convergence
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• v.22 no.2
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• pp.143-151
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• 2024

This study compared the health behaviors, health related clinical characteristics between individuals with Glycated Hemoglobin A1C≧6.5% and < 6.5% in 30~59yr. Factors that were associated with A1C were identified by sex, health behaviors, health literacy. This study was an observational study with a cross-sectional design based on data from 2019~2021 Korea National Health and Nutrition Examination Survey. Multiple logistic regression analysis was employed to compute the odds ratios of health behaviors to identify the risk factors for Glycated Hemoglobin. The prevalence of A1C≧6.5% among the total was 79.4%(weighted %, n=348). In the A1C≧6.5%, 71.8% were men. In univariate logistic regression for A1C≧6.5%, sex, duration with diabetes, and body mass index(BMI) were influencing factors. In multiple logistic regression by sex, the factors associated with A1C≧6.5 in women were as follows: education(OR 4.5; 95% CI:1.1, 18.5), duration with diabetes(OR 2.9; 95% CI 1.1, 7.9). Strategies should be targeted to improve health behaviors and clinical characteristics for those in their sex, women in low education level, duration with diabetes. Moreover, healthcare providers should understand the barriers to health behaviors and health literacy to effectively deliver healthcare service.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.91-99
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• 2024

Piping systems are crucial facilities used in various industries, particularly in areas related to daily life and safety. Piping systems are fixed to the main structures of buildings and facilities but do not support external loads and serve as non-structural elements performing specific functions. Piping systems are affected by relative displacements owing to phase differences arising from different behaviors between two support points under seismic loads; this can cause damage owing to the displacement-dominant cyclic behavior. Fittings and joints in piping systems are representative elements that are vulnerable to seismic loads. To evaluate the seismic performance and limit states of fittings and joints in piping systems, a high-stroke actuator is required to simulate relative displacements. However, this is challenging because only few facilities can conduct these experiments. Therefore, element-level experiments are required to evaluate the seismic performance and limit states of piping systems connected by fittings and joints. This study proposed a method to evaluate the seismic performance of an elbow specimen that includes fittings and joints that are vulnerable to seismic loads in vertical piping systems. The elbow specimen was created by connecting straight pipes to both ends of a 90° pipe elbow using flexible groove joints. The seismic performance of the elbow specimen was evaluated using a cyclic loading protocol based on deformation angles. To determine the margin of the evaluated seismic performance, the limit states were assessed by applying cyclic loading with a constant amplitude.

• Journal of Service Research and Studies
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• v.14 no.2
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• pp.158-177
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• 2024

This paper proposes and tests a theoretical model of the relational link between a novel form of customer-perceived fairness for a reward design (distributive peer justice climate) and C2C helping intention via community identification and online C2C interaction (friend-, neighboring customer-, audience-interaction) qualities in a collective consumption context (MMORPG). To test hypotheses, we amassed survey data within a collective consumption context (massively multiplayer online role-playing games, MMORPGs). We used structural equation modeling in analyzing the survey data. The results reveal that user-perceived distributive peer justice climate for a reward design enhances their C2C helping intention via community identification and C2C interactions in MMORPG contexts. Collective consumption-type service managers should focus on promoting the user-perceived distributive peer justice climate for their reward system to enhance users' present C2C co-creation experience (community identification, C2C interaction) and future C2C co-creation behavior (helping intention). By adopting an intra-unit level distributive justice concept (customer-perceived distributive peer justice climate) to a reward design in a collective consumption context (MMORPGs), this study informed collective consumption-type service managers of the importance of its management.

• Computers and Concrete
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• v.33 no.5
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• pp.497-507
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• 2024

In squat reinforced concrete walls, the displacement capacity for lateral deformation is low and the ability to resist the axial load can quickly be lost, generating collapse. This work consists of testing two squat reinforced concrete walls. One of the specimens is built with conventional detailing of reinforced concrete walls, while the second specimen is built applying an alternative design, including stirrups along the diagonal of the wall to improve its ductility. This solution differs from the detailing of beams or coupling elements that suggest building elements equivalent to columns located diagonally in the element. The dimensions of both specimens correspond to a wall with a low aspect ratio (1:1), where the height and length of the specimen are 1.4 m, with a thickness of 120 mm. The alternative wall included stirrups placed diagonally covering approximately 25% of the diagonal strut of the wall with alternative detailing. The walls were tested under a constant axial load of 0.1f'cAg and a cyclic lateral displacement was applied in the upper part of the wall. The results indicate that the lateral strength is almost identical between both specimens. On the other hand, the lateral displacement capacity increased by 25% with the alternative detailing, but it was also able to maintain the 3 complete hysteretic cycles up to a drift of 2.5%, reaching longitudinal reinforcement fracture, while the base specimen only reached the first cycle of 2% with rapid degradation due to failure of the diagonal compression strut. The alternative design also allows 46% more energy dissipation than the conventional design. A model was used to capture the global response, correctly representing the observed behavior. A parametric study with the model, varying the reinforcement amount and aspect ratio, was performed, indicating that the effectiveness of the alternative detailing can double de drift capacity for the case with a low aspect ratio (1.1) and a large longitudinal steel amount (1% in the web, 5% in the boundary), which decreases with lower amounts of longitudinal reinforcement and with the increment of aspect ratio, indicating that the alternative detailing approach is reasonable for walls with an aspect ratio up to 2, especially if the amount of longitudinal reinforcement is high.

• Journal of Preventive Medicine and Public Health
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• v.57 no.3
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• pp.288-297
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• 2024

Objectives: This study explored the prevalence and predictors of alcohol and cannabis co-use among 9263 Filipino adolescents, using data from the 2019 Global School-based Student Health Survey (GSHS). Methods: We conducted a cross-sectional secondary analysis of the GSHS, targeting adolescents aged 13-17 years and excluding cases with incomplete data on alcohol and cannabis use. Our analysis employed the bivariate chi-square test of independence and multivariable logistic regression using Stata version 18 to identify significant predictors of co-use, with a p-value threshold set at 0.05. Results: The weighted prevalence of co-users was 4.2% (95% confidence interval [CI], 3.4 to 5.3). Significant predictors included male sex (adjusted odds ratio [aOR], 4.50; 95% CI, 3.31 to 6.10; p<0.001) and being in a lower academic year, specifically grade 7 (aOR, 4.08; 95% CI, 2.39 to 6.99; p<0.001) and grade 8 (aOR, 2.20; 95% CI, 1.30 to 3.72; p=0.003). Poor sleep quality was also a significant predictor (aOR, 1.77; 95% CI, 1.29 to 2.44; p<0.001), as was a history of attempted suicide (aOR, 5.31; 95% CI, 4.00 to 7.06; p<0.001). Physical inactivity was associated with lower odds of co-use (aOR, 0.45; 95% CI, 0.33 to 0.62; p<0.001). Additionally, non-attendance of physical education classes (aOR, 1.48; 95% CI, 1.06 to 2.05; p=0.021), infrequent unapproved parental checks (aOR, 1.37; 95% CI, 1.04 to 1.80; p=0.024), and lower parental awareness of free-time activities (aOR, 0.63; 95% CI, 0.45 to 0.87; p=0.005) were associated with higher odds of co-use. Factors not significantly linked to co-use included age group, being in grade 9, always feeling lonely, having no close friends, being bullied outside school, and whether a parent or guardian understood the adolescent's worries. Conclusions: The findings highlight the critical need for comprehensive interventions in the Philippines, addressing not only physical inactivity and parental monitoring but also focusing on sex, academic grade, participation in physical education classes, sleep quality, and suicide attempt history, to effectively reduce alcohol and cannabis co-use among adolescents.

• Journal of Oriental Neuropsychiatry
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• v.35 no.2
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• pp.141-151
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• 2024

Objectives: To compare symptoms and characteristics among patients diagnosed with Hwabyung according to their yin-yang personality types. Methods: A structured clinical interview was conducted to diagnose Hwabyung, followed by a cross-sectional study involving a total of 118 Hwabyung patients (95 females). Various measures including the Sasang Personality Questionnaire (SPQ), Hwabyung Comprehensive Test (HCT), HwaByung Scale (HBS), State-Trait Anger Expression Inventory (STAXI), Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory (BAI), Eogul Scale (ES), and Patient Health Questionnaire-15 (PHQ-15) were administered. Results: SPQ-total showed significant negative correlations with HBS-personality and STAXI-control, and a significant positive correlation with STAXI-out. SPQ-behavior showed significant positive correlations with HBS-symptom, STAXI-trait, STAXI-in, STAXI-out, BDI-II, BAI, ES, and PHQ-15. SPQ-cognition exhibited significant negative correlations with HBS-personality, STAXI-control, and ES. SPQ-emotion had significant negative correlations with HBS-personality and STAXI-in and a significant positive correlation with STAXI-out. SPQ-Yin demonstrated a significantly higher HBS-personality than SPQ-Yang. SPQ-Yang exhibited significantly higher STAXI-out than SPQ-Yin, whereas SPQ-Yin showed significantly higher STAXI-control and STAXI-in than SPQ-Yang. Although differences in depression, anxiety, resentment, and physical symptoms between yin and yang were not statistically significant, variations in interpretation criteria were observed. Conclusions: Anger expression patterns and physical/psychological symptoms among Hwabyung patients are different based on their yin-yang personality types. These findings can inform the prediction of symptoms in Hwabyung patients according to their yin-yang personality types and aid in establishing appropriate treatment plans.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.1
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• pp.11-18
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• 2024

Recently, there have been attempts to claim the hair moisturizing effect for a hair care product, however there has not yet been an official evaluation method because heating temperature for hair has not been established. This study was conducted to establish a quantitative evaluation for hair water content. In order to observe the behavior of water inside hair, heat was applied to hair with various temperatures using thermogravimetric dry residue. As the heating temperature increased, the amount of moisture released from the hair increased. As a result of evaluating hair using a differential scanning calorimeter (DSC), a unique phenomenon in which a rapid endothermic reaction occurs around 75 ℃ was observed. This phenomenon was also observed in different ethnic hair. In hair that damaged the hair cuticle barrier with oxidation and heat, this rapidly rising endothermic reaction temperature occurred at 77 ℃, which was slightly higher, and 73 ℃ was observed when this hair was applied with polar oil, conditioning polymer, or keratin protein. To determine how this reaction affects the hair surface, friction test was performed using an atomic force microscope. When heated above 75 ℃, cuticle friction increased, however when heated above 90 ℃, there was no change in hair cuticle friction. Finally, it was confirmed that around 75 ℃ is the critical temperature at which desorption of water bound to the hair occurs. It is suggested that a heating temperature of 75 ℃ is the optimal temperature for detecting and quantifying the moisture content of hair, and that approximately 10% detected at 75 ℃ can be a standard value for hair moisture content.

• Journal of Nutrition and Health
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• v.57 no.2
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• pp.244-260
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• 2024

Purpose: With the 2021 revision of dietary guidelines in Korean emphasizing environmentally sustainable dietary practices, this study attempted to develop an evaluation tool to comprehensively evaluate the degree of practice and compliance with food and nutrient intake, dietary habits, and dietary culture guidelines based on the revised dietary guidelines. Methods: The candidate evaluation items were collected by reviewing 934 literature reviews on domestic and foreign dietary evaluations. Fifty-nine candidate items were derived by selecting the items corresponding to dietary guidelines. The content validity ratio (CVR) cutoff point evaluation was conducted with 11 experts to delete 11 items that did not meet the CVR standard. Fifty-five pilot survey candidate items were selected through revision and additional process according to expert opinion. Seventy final candidate items were selected by adding 15 questions for validity verification and reference. A pilot survey was conducted online and offline on 332 adults aged 19-64 in Seoul and the metropolitan area, and exploratory factor analysis was used to verify the construct validity of the evaluation items. Through exploratory factor analysis, the Kaiser-Meyer-Olkin, Bartlett's sphericity test, variance explained, and Cronbach's alpha criteria were confirmed in each process. Results: Exploratory factor analyses derived three criteria: food and nutrient intakes (11 items), eating behaviors (9 items), and dietary culture (14 items), consisting of 34 evaluation items. Conclusion: The present scale was validated and can be used for comprehensive evaluations of the dietary guidelines for Korean adults in a simple way.